The invention generally relates to a system to connect conduit sections in a subterranean well, and more particularly, the invention relates to a system to form a releasable connection between conduit sections and to limit movement of the conduit sections with respect to each other when connected together.
Several different conduit members typically are present in a subterranean well for purposes of communicating well fluids, hydraulic fluids, etc. Some of these conduit members may be formed from connected conduit sections. More particularly, one end of each conduit section may form a female connector, and the other end of the conduit section may form a male connector. The female connector of each conduit section mates with the male connector of an adjacent conduit section so that the conduit sections may be connected in an end-to-end fashion to form the tubular member. An example of a connection between two such conduit sections is depicted in FIG. 1.
Referring to FIG. 1, as an example, the connection may be formed from a female connector assembly 10 (that is attached to the upper end 21 of a lower conduit section 12) and the lower end 20 (forming a male connector) of an upper 14 conduit section. The connection is established by lowering the upper conduit section 14 downhole into the wellbore so that the lower end 20 of the upper conduit section 14 enters, or “stabs,” an upper opening 19 of the female assembly 10.
As depicted in FIG. 1, for purposes of guiding the lower end 20 of the upper conduit section 14 into the female connector assembly 10, the assembly 10 may include such features as an inclined surface 11 (of an upper housing section 17 of the assembly 10) that is slanted toward the opening 19. Furthermore, for purposes of forming a seal between the upper 12 and lower 14 conduit sections, the female connector assembly 10 may include a seal assembly 18 that is contained within a middle section 15 of the assembly 10. The seal assembly 18 may include a stack of annular seals that reside between the exterior surface of the upper conduit section 14 and the interior surface of the middle section 15 of the female connector assembly 10. The seal between the conduit sections 12 and 14 exists only for the condition in which a gap d between the lower end 20 of the upper conduit section 14 and the upper end 21 of the lower conduit section 12 remains smaller than a specified distance (0.0250 inches, as an example). For a gap d greater than this specified distance, the integrity of the seal that is formed between the conduit sections 12 and 14 may be affected.
In a conventional well system, the conduit sections 12 and 14 may form part of a hydraulic conduit string that is used, as its name implies, for purposes communicating hydraulic fluid downhole. This hydraulic conduit string may be located inside or outside of a production tubing string (not shown) of the well. Thus, each conduit section 12,14 may be associated with and located inside or outside of a production tubing section (not shown). As a more specific example, the lower conduit section 12 may be located inside or outside of a lower production tubing section, and the upper conduit section 14 may be located inside or outside of an upper production tubing section. Adjacent production tubing sections (that form part of the production tubing string) may be connected together concurrently with the connection of the associated adjacent conduit sections (that form part of the hydraulic conduit string).
A potential difficulty with the above-described system is the criteria that for establishing an acceptable connection between the production tubing sections may be significantly different than the criteria for establishing an acceptable connection between the conduit sections 12 and 14. More specifically, the acceptable gap between adjacent ends of the production tubing sections may be significantly larger than the acceptable gap between the upper 20 and lower 21 ends of the conduit sections 12 and 14. By way of example, it may be acceptable for a gap of 0.75 inches or less (as an example, for comparison) to exist between the lower end of an upper production tubing section and the upper end of an adjacent lower production tubing section. This acceptable gap between production tubing sections may be significantly larger than the acceptable gap of 0.025 inches or less (as an example, for comparison) between the upper 20 and lower 21 ends of the conduit sections 12 and 14. Due to forces that are exerted on the conduit sections 12 and 14 by the production tubing sections, a movement between the production tubing sections may cause a relatively large movement (i.e., a movement greater than 0.025 inches, for example) between the adjacent ends of the conduit sections 12 and 14 and thus, may impair the seal between the conduit sections 12 and 14.
Thus, there is a continuing need for a better system for connecting tubular sections in a subterranean well.